U.S. Pat. No. 4,491,258 has disclosed bags having three storage elements capable of being stiffened by reinforcing strips in a knapsack mode. In the bicycle pannier mode, these reinforcing strips are to keep the bags from hitting the spokes unchecked when the bicycle is in motion.
When the known bags are used as bicycle panniers, they are placed over bicycle racks so that two of the three storage elements of a bag hang down next to the rear wheel and next to the front wheel. Two smaller front wheel bags are to be interconnected to form a unit by a divisible zip fastener, by snap fasteners and by elastic bungy cords before they are placed on the front rack. The bungy cords are then fastenable by hooks to the rack supports. The larger bag is intended for fastening to the rear rack and is fixed to the rack supports or bicycle frame with the aid of straps.
When the three bags are assembled to form a knapsack, they are first placed side by side with the larger rear wheel bag arranged between the then parted front wheel bags. The three bags are interconnected by connecting respective zip fasteners and snap fasteners. To stiffen the knapsack thus composed, the strips are slid into sleeves provided on the back of the rear wheel bag. To impart greater dimensional stability to the knapsack as a whole, the knapsack assembled from the bags is provided with a plurality of straps surrounding it lengthwise and crosswise.
Although transport of the bags on a bicycle with the aid of the known fastening devices is satisfactory on well-surfaced roads, this fastening mode is inadequate when riding on bad stretches of road and particularly cross-country. Through the shocks occuring, laden bags are liable to slip due to their inertia, often causing falls particularly when negotiating curves or when riding cross-country. When heavily loaded, the cords and straps are under such a strain that they often tear or the seams sewing the straps onto the bag are ripped open.
Furthermore the use of racks proves to be disadvantageous for transportation of the bicycle laden with bags, because the wheels often have to be taken off the bicycle for reasons of space. The racks remaining on the bicycle frame are nevertheless in the way and also susceptible to damage. It is troublesome to remove the racks from the bicycle, especially since in addition to carrying the bags a cyclist then also has to carry the detached racks.
U.S. Pat. No. 4,433,802 has disclosed a bicycle pannier--knapsack device having a rack which is detachable from the bicycle and is usable as a frame when two carried bags are combined to form a knapsack.
This device has the drawback, however, that the parts of the rack used as the knapsack frame have to be interconnected with the aid of several clevis pins. Even though this ensures that the rack members can to some degree be varied to accommodate the size of the person carrying the knapsack, change of mode is made complicated and tedious by the bothersome removal of the spring clip fasteners.
The known fastening devices fail to provide an acceptable solution, particularly for sporty cyclists who are known to be very exacting when it comes to the functionality of the items they use and therefore expect that the bags fastened to the bicycle can be converted and assembled to form a knapsack in no time.